Computing device for processing environmental sensed conditions

ABSTRACT

A method includes a computing device transmitting a radio frequency (RF) signal to a passive wireless sensor. The RF signal includes a carrier frequency signal and a modulated sense request signal. The method further includes, in response to the modulated sense request signal, receiving, by the computing device, a response RF signal that includes the carrier frequency signal and a coded sense response signal from the passive wireless sensor. The coded sense response signal is representative of a sensed environmental condition by the passive wireless sensor. The method further includes generating, by the computing device, an environmental condition value based on the coded sense response signal and an environmental conversion information.

CROSS REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. § 119(e) to U.S. Provisional Application No. 62/196,036,entitled “PASSIVE RFID SOFTWARE DEFINED RADIO SYSTEM”, filed Jul. 23,2015, which is hereby incorporated herein by reference in its entiretyand made part of the present U.S. Utility Patent application for allpurposes.

The present U.S. Utility patent application also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 14/150,392, entitled “METHOD AND APPARATUS FORDETECTING RF FIELD STRENGTH”, filed Jan. 8, 2014, which is a divisionalof U.S. Utility application Ser. No. 13/209,420, entitled “METHOD ANDAPPARATUS FOR DETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, nowU.S. Pat. No. 8,749,319, issued on Jun. 10, 2014, which claims prioritypursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No.61/428,170, entitled “METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”,filed Dec. 29, 2010 and U.S. Provisional Application No. 61/485,732,entitled “METHOD AND APPARATUS FOR SENSING ENVIRONMENTAL CONDITIONSUSING AN RFID TAG”, filed May 13, 2011, all of which are herebyincorporated herein by reference in their entirety and made part of thepresent U.S. Utility patent application for all purposes.

U.S. Utility application Ser. No. 13/209,420 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. Utilitypatent application for all purposes.

The present U.S. Utility patent application also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 14/256,877, entitled “METHOD AND APPARATUS FORSENSING ENVIRONMENT USING A WIRELESS PASSIVE SENSOR”, filed Apr. 18,2014, which claims priority pursuant to 35 U.S.C. § 119(e) to U.S.Provisional Application No. 61/814,241, entitled “RFID ENVIRONMENTALSENSOR”, filed Apr. 20, 2013; U.S. Provisional Application No.61/833,150, entitled “RESONANT ANTENNA”, filed Jun. 10, 2013; U.S.Provisional Application No. 61/833,167, entitled “RFID TAG”, filed Jun.10, 2013; U.S. Provisional Application No. 61/833,265, entitled “RFIDTAG”, filed Jun. 10, 2013; U.S. Provisional Application No. 61/871,167,entitled “RESONANT ANTENNA”, filed Aug. 28, 2013; U.S. ProvisionalApplication No. 61/875,599, entitled “CMF ACCURATE SENSOR”, filed Sep.9, 2013; U.S. Provisional Application No. 61/896,102, entitled “RESONANTANTENNA”, filed Oct. 27, 2013; U.S. Provisional Application No.61/929,017, entitled “RFID ENVIRONMENTAL SENSOR”, filed Jan. 18, 2014;U.S. Provisional Application No. 61/934,935, entitled “RFIDENVIRONMENTAL SENSOR”, filed Feb. 3, 2014; all of which are herebyincorporated herein by reference in their entirety and made part of thepresent U.S. Utility patent application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/209,420, entitled “METHOD AND APPARATUS FORDETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.8,749,319, issued on Jun. 10, 2014, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility patentapplication for all purposes.

U.S. Utility application Ser. No. 13/209,420 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. Utilitypatent application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/209,425, entitled “METHOD AND APPARATUS FORDETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.9,048,819, issued on Jun. 2, 2015, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility patentapplication for all purposes.

U.S. Utility application Ser. No. 13/209,425 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. Utilitypatent application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/467,925, entitled “ROLL-TO-ROLL PRODUCTION OFRFID TAGS”, filed May 9, 2012, which is a continuation-in-part of U.S.Utility application Ser. No. 13/209,425, entitled “METHOD AND APPARATUSFOR DETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.9,048,819, issued on Jun. 2, 2015, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility patentapplication for all purposes.

U.S. Utility application Ser. No. 13/209,425 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. Utilitypatent application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION 1. Technical Field of the Invention

This application relates generally to wireless data communicationsystems and more particularly to processing data representative ofenvironmental sensed conditions.

2. Description of Related Art

Wireless communication systems are known to include wirelesstransceivers that communication directly and/or over a wirelesscommunication infrastructure. In direct wireless communications, a firstwireless transceiver includes baseband processing circuitry and atransmitter to convert data into a wireless signal (e.g., radiofrequency (RF), infrared (IR), ultrasound, near field communication(NFC), etc.). Via the transmitter, the first wireless transceivertransmits the wireless signal. When a second wireless transceiver is inrange (e.g., is close enough to the first wireless transceiver toreceive the wireless signal at a sufficient power level), it receivesthe wireless signal via a receiver and converts the signal intomeaningful information (e.g., voice, data, video, audio, text, etc.) viabaseband processing circuitry. The second wireless transceiver maywirelessly communicate back to the first wireless transceiver in asimilar manner.

Examples of direct wireless communication (or point-to-pointcommunication) include walkie-talkies, Bluetooth, ZigBee, RadioFrequency Identification (RFID), etc. As a more specific example, whenthe direct wireless communication is in accordance with RFID, the firstwireless transceiver may be an RFID reader and the second wirelesstransceiver may be an RFID tag.

For wireless communication via a wireless communication infrastructure,a first wireless communication device transmits a wireless signal to abase station or access point, which conveys the signal to a wide areanetwork (WAN) and/or to a local area network (LAN). The signal traversesthe WAN and/or LAN to a second base station or access point that isconnected to a second wireless communication device. The second basestation or access point sends the signal to the second wirelesscommunication device. Examples of wireless communication via aninfrastructure include cellular telephone, IEEE 802.11, public safetysystems, etc.

In many situations, direct wireless communication is used to gatherinformation that is then communicated to a computer. For example, anRFID reader gathers information from RFID tags via direct wirelesscommunication. At some later point in time (or substantiallyconcurrently), the RFID reader downloads the gathered information to acomputer via a direct wireless communication or via a wirelesscommunication infrastructure.

In many RFID systems, the RFID tag is a passive component. As such, theRFID tag has to generate one or more supply voltages from the RF signalstransmitted by the RFID reader. Accordingly, a passive RFID tag includesa power supply circuit that converts the RF signal (e.g., a continuouswave AC signal) into a DC power supply voltage. The power supply circuitincludes one or more diodes and one or more capacitors. The diode(s)function to rectify the AC signal and the capacitor(s) filter therectified signal to produce the DC power supply voltage, which powersthe circuitry of the RFID tag.

Once powered, the RFID tag receives a command from the RFID reader toperform a specific function. For example, if the RFID tag is attached toa particular item, the RFID tag stores a serial number, or some otheridentifier, for the item. In response to the command, the RFID tagretrieves the stored serial number and, using back-scattering, the RFIDtag transmits the retrieved serial number to the RFID reader.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice in accordance with the present invention;

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice communicating with a passive wireless sensor in accordance withthe present invention;

FIG. 4 is a schematic block diagram of an embodiment of a portion of asensor computing device in accordance with the present invention;

FIG. 5 is a diagram of an example of an RF signal in accordance with thepresent invention;

FIG. 6 is a logic diagram of an example of a sensor computing devicecommunicating with a passive wireless sensor in accordance with thepresent invention;

FIG. 7 is a logic diagram of another example of a sensor computingdevice communicating with a passive wireless sensor in accordance withthe present invention;

FIG. 8 is a logic diagram of an example of generating an environmentalcondition value in accordance with the present invention;

FIG. 9 is a logic diagram of an example of calibrating communicationbetween a sensor computing device communicating and a passive wirelesssensor in accordance with the present invention;

FIG. 10 is a logic diagram of an example of a sensor computing devicecommunicating with multiple passive wireless sensors in accordance withthe present invention;

FIG. 11 is a diagram of an example of frequency hopping in accordancewith the present invention; and

FIG. 12 is a logic diagram of an example of frequency hoppingcommunication between a sensor computing device and a passive wirelesssensor in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem 10 that includes a plurality of sensor computing device 12, aplurality of user computing devices 14, a plurality of passive wirelesssensors 16-1 through 16-4, one or more wide area networks (WAN), and oneor more local area networks (LAN). The passive wireless sensors 16-1through 16-4, when activated, sense one or more of a variety ofconditions. For example, one passive wireless sensor senses for thepresence, absence, and/or amount of moisture in a given location (e.g.,in a room, in a manufactured item or component thereof (e.g., avehicle), in a bed, in a diaper, etc.). As another example, a passivewireless sensor senses pressure on and/or in a particular item (e.g., ona seat, on a bed, in a tire, etc.)

As yet another example, a passive wireless sensor senses temperaturewithin a space and/or of an item (e.g., surface temperature of the item,in a confined space such as a room or a box, etc.). As a furtherexample, a passive wireless sensor senses humidity within a space (e.g.,a room, a closet, a box, a container, etc.). As a still further example,a passive wireless sensor senses the presence and/or percentages of agas within a space (e.g., carbon monoxide in a car, carbon monoxide in aroom, gas within a food container, etc.). As an even further example, apassive wireless sensor senses the presence and/or percentages of alight within a space. As yet a further example, a passive wirelesssensor senses the presence, percentages, and/or properties of one ormore liquids in a solution. In one more example, a passive wirelesssensor senses location proximity of one item to another and/or theproximity of the passive wireless sensor to an item (e.g., proximity toa metal object, etc.).

In general, the sensor computing devices 12 function to collect thesensed data from the passive wireless sensors and process the senseddata. For example, a passive wireless sensor generates a coded valuerepresentative of a sensed condition (e.g., amount of moisture). Asensor computing device 12 receives the coded value and processes it todetermine an accurate measure of the sensed condition (e.g., a valuecorresponding to the amount of moisture such as 0% saturated, 50%saturated, 100% saturated, etc.).

The user computing devices 14 communication with one or more of thesensor computing devices 12 to gather the accurate measures of sensedconditions for further processing. For example, assume that the wirelesscommunication system is used by a manufacturing company that hasmultiple locations for assembly of its products. In particular, LAN 1 isat a first location where a first set of components of products areprocessed and the LAN 2 is at a second location where second componentsof the products and final assembly of the products occur. Further assumethat the corporate headquarters of the company is at a third location,where it communicates with the first and second locations via the WANand LANs.

In this example, the sensor computing device 12 coupled to LAN 1collects and processes data regarding the first set of components assensed by passive wireless sensors 16-1 and 16-2. The sensor computingdevice 12 is able to communicate this data to the user computing device14 coupled to the LAN 1 and/or to the computing device 14 at corporateheadquarters via the WAN. Similarly, the sensor computing device 12coupled to LAN 2 collects and processes data regarding the second set ofcomponents and final assembly as sensed by passive wireless sensors 16-3and 16-4. This sensor computing device 12 is able to communicate thisdata to the user computing device 14 coupled to the LAN 2 and/or to thecomputing device 14 at corporate headquarters via the WAN. In such asystem, real time monitor is available locally (e.g., via the LAN) andis further available non-locally (e.g., via the WAN). Note that any ofthe user computing devices 14 may receive data from the any of thesensor computing devices 12 via a combination of LANs and the WAN.

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice 12 and/or 14 that includes a computing core 20, one or more inputdevices 48 (e.g., keypad, keyboard, touchscreen, voice to text, etc.),one or more audio output devices 50 (e.g., speaker(s), headphone jack,etc.), one or more visual output devices 46 (e.g., video graphicsdisplay, touchscreen, etc.), one or more universal serial bus (USB)devices, one or more networking devices (e.g., a wireless local areanetwork (WLAN) device 54, a wired LAN device 56, a wireless wide areanetwork (WWAN) device 58 (e.g., a cellular telephone transceiver, awireless data network transceiver, etc.), and/or a wired WAN device 60),one or more memory devices (e.g., a flash memory device 62, one or morehard drives 64, one or more solid state (SS) memory devices 66, and/orcloud memory 96), one or more peripheral devices, and/or a transceiver70.

The computing core 20 includes a video graphics processing unit 28, oneor more processing modules 22, a memory controller 24, main memory 26(e.g., RAM), one or more input/output (I/O) device interface module 36,an input/output (I/O) interface 32, an input/output (I/O) controller 30,a peripheral interface 34, one or more USB interface modules 38, one ormore network interface modules 40, one or more memory interface modules42, and/or one or more peripheral device interface modules 44. Each ofthe interface modules 36-44 includes a combination of hardware (e.g.,connectors, wiring, etc.) and operational instructions stored on memory(e.g., driver software) that is executed by the processing module 22and/or a processing circuit within the respective interface module. Eachof the interface modules couples to one or more components of thecomputing device 12-14. For example, one of the IO device interfacemodules 36 couples to an audio output device 50. As another example, oneof the memory interface modules 42 couples to flash memory 62 andanother one of the memory interface modules 42 couples to cloud memory68 (e.g., an on-line storage system and/or on-line backup system).

The transceiver 70 is coupled to the computing core 20 via a USBinterface module 38, a network interface module 40, a peripheral deviceinterface module 44, or a dedicated interface module (not shown).Regardless of how the transceiver 70 is coupled to the computing core,it functions to communication with the passive wireless sensors.

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice 12 communicating with a passive wireless sensor 16 (e.g., any oneof 16-1 through 16-4). The sensor computing device 12 is illustrated ina simplified manner; as such, it shown to include the transceiver 70, anantenna 96, the processing module 22, and the memory (e.g., one or more26 and 62-68). The passive wireless sensor 16 includes an antenna 80, aone or more sensing elements 58, a power harvesting circuit 82, a powerdetection circuit 86, a processing module 84, memory 88, a tuningcircuit 90, a receiver section 92, and a transmitter section 94.

In an example, the sensing element 58 of the passive wireless sensor 16senses an environmental condition of an object. The environmentcondition includes, but is not limited to, one or more of moisture,temperature, pressure, humidity, altitude, sonic wave (e.g., sound),human contact, surface conditions, tracking, location, etc. The objectincludes one or more of, but is not limited to, a box, a personal item(e.g., clothes, diapers, etc.), a pet, an automobile component, anarticle of manufacture, an item in transit, etc. The sensing element 58senses the environmental condition (e.g., moisture) and, as a result ofthe sensed condition, the sensing element 58 affects an operationalparameter (e.g., input impedance, quality factor, frequency, etc.) of anRF front end of the passive wireless sensor. Note that the RF front endincludes one or more of the antenna 80, the tuning circuit 90, thetransmitter section 94, the receiver section 92.

As a specific example, the sensing element 58, as a result of the sensedenvironmental condition, affects the input impedance of the antennastructure 80 and/or of the tuning circuit 90 (e.g., a tank circuit thatincludes one or more capacitors and one or inductors having a resonantfrequency corresponding to the carrier frequency of the RF signal). Inresponse to the impedance change, the processing module 84 adjusts theresonant frequency of the tuning circuit 90 to compensate for the changein input impedance caused by the sensed environmental condition. Theamount of adjustment is reflective of the level of the environmentalcondition (e.g., a little change corresponds to a little moisture; alarge change corresponds to a large amount of moisture). The processingmodule 84 generates a coded value to represent the amount of adjustmentand conveys the coded value to the sensor computing device 12 via thetransmitter section 94 and the antenna 80 using back-scattering.

In addition to processing the sensed environmental condition, theprocessing module 84 processes a power level adjustment. For example,the power detection circuit 86 detects a power level of the received RFsignal. In one embodiment, the processing module interprets the powerlevel and communicates with the sensor computing device 12 to adjust thepower level of the RF signal transmitted by the computing device 12 to adesired level (e.g., optimal for accuracy in detecting the environmentalcondition). In another embodiment, the processing module 84 includes thereceived power level data with the environmental sensed data it sends tothe sensor computing device 12 so that the computing device can factorthe power level into the determination of the environmental condition.One or more of these concepts will be described in greater detail withreference to one or more of FIGS. 4-12.

FIG. 4 is a schematic block diagram of an embodiment of a portion of asensor computing device 12 that includes the processing module 22 andthe transceiver 70. The processing module 22 includes a data processingunit 100, a data modulator 102, and a data demodulator 104. Thetransceiver 70 includes an up conversion module 106, a transmitamplifier 108 (e.g., a power amplifier), a transmit/receive unit (T/R),a receiver amplifier 110 (e.g., a low noise amplifier), a downconversion module 112, and a local oscillation generator (LOGEN) 114.

In an example of operation, the local oscillation generator (LOGEN) 114generates, based on an input from the data processing module 22 (e.g.,from the data processing unit) to generate a continuous wave signal at aparticular carrier frequency (e.g., in the range of 902-928 MHz). Toestablish communication with the passive wireless sensor 16, thetransceiver 70 first transmits, as an RF signal 120 the continuous wavesignal at the particular carrier frequency 122 as shown in FIG. 5.During the startup, or power up, phase, the processing module 22 is notgenerating outbound data 116.

With reference to both FIGS. 4 and 5, when the passive wireless sensor16 is powered up (as will be described below with reference to one ormore of FIGS. 6-12), the data processing unit 100 generates outbounddata 116 (e.g., a digital representation of a sense command). The datamodulator 102 converts the outbound data 116 into modulated data andprovides the modulated data to the up conversion module 106.

The up conversion module 106 mixes the continuous wave signal at aparticular carrier frequency with the modulation data to produce themodulated sense request signal 124 of the RF signal 120. For example,the computing device 12 uses amplitude shifting keying (ASK) to generatethe modulated sense request signal 124. As such, the modulated dataproduced by the data modulator 102 adjusts the amplitude of thecontinuous wave signal. In particular, for a digital value of 1, themodulated data is a first amplitude gain to change the amplitude of thecontinuous wave signal to a first level or a first pattern (e.g., perRFID standard ISO/IEC 18000-6) and, for a digital value of 0, themodulated data is a second amplitude gain to change the amplitude of thecontinuous wave signal to a second level or to a second a pattern (e.g.,per the RFID standard). After transmitting the modulated sense requestsignal 124, the transmitter resumes sending the continuous wave (i.e.,carrier frequency) signal 122.

The passive wireless sensor 16 receives the RF signal 120, down convertsand demodulates it to recover the sense request signal (i.e., theoutbound data 116). In response to the request or automatically, thepassive wireless sensor 16 senses an environmental condition asdiscussed with reference to FIG. 3. The passive wireless sensor 16generates a coded value representing a change in an operating parameterof its front end. Utilizing backscattering, the passive wireless sensormodulates the continuous wave signal with the coded value to produce anRF response signal.

The computing device receives the RF response signal via the antenna 96and down converts it via the down conversion module 112. The datademodulator 104 demodulates the down converted signal to recapture thecoded value as inbound data 118. As an example, the down conversionmodule 112 mixes the continuous wave signal produced by the LOGEN 114with the RF response signal to produce a baseband, or near baseband,inbound signal. The data demodulator 104 demodulates the baseband, ornear baseband, inbound signal to produce the inbound data 118. As aspecific example of ASK demodulation, the down conversion module and thedata demodulator perform inverse ASK functions of the data modulator 102and the up conversion module 106.

FIG. 6 is a logic diagram of an example of a sensor computing devicecommunicating with a passive wireless sensor. The method begins at step130 where the sensor computing device transmits a radio frequency (RF)signal to a passive wireless sensor. The RF signal includes a carrierfrequency signal and a modulated sense request signal. An example of theRF signal was discussed with reference to FIG. 5.

The method continues at step 132 where the passive wireless sensorreceives the RF signal. The method continues at step 134 where thepassive wireless sensor generates a power supply voltage from thecarrier frequency signal. The method continues at step 136 where thepassive wireless sensor determines received signal strength (RSSI) ofthe RF signal. Examples of creating power and measuring RSSI werediscussed with reference to FIG. 3.

The method continues at step 138 where the passive wireless sensordetermines whether the received signal strength of the RF signal is at adesired level. For example, to measure one or more environmentalconditions, the passive wireless sensor includes a sensing element that,when exposed to the environmental condition (e.g., moisture), causes achange to an operational parameter (e.g., impedance) of the front-end ofthe passive wireless sensor (e.g., the sensing element, the antenna, thetuning circuit, the transmitter section, and/or the receiver section).The supply voltage and corresponding current are variables that can alsoaffect the operation parameter. Thus, to remove the supply voltage andcurrent as variables, they are set to particular levels, whichcorresponds to a particular level (i.e., the desired level) of the RSSIof the RF signal. If not, the method continues at step 140 where thepassive wireless sensor sends an RSSI signal to the computing device 12.As an alternative to the passive wireless sensor determining whether theRSSI is at the desired level, it skips step 138 and sends the RSSIsignal to the computing device, which determines whether the RSSI is atthe desired level.

The method continues at step 142 where the sensor computing devicedetermines whether the transmit power needs to be adjusted based on theRSSI. If yes, the method continues at step 144 where the sensorcomputing device adjusts the transmit power and retransmits the RFsignal at the adjusted power level. This may be an iterative process ora single calculated process to adjust the transmit power.

Once the RSSI is at the desired level, the method continues at step 146where the sensor computing device transmits the RF signal that includesthe modulated sense request signal. The method continues at step 148where the passive wireless sensor down converts and/or demodulates theRF signal to recover the sense request signal. In response the senserequest signal, the method continues at step 150 where the passivewireless sensor measures, or retrieves a stored measurement, anoperational parameter of a front-end of the passive wireless sensor. Themethod continues at step 152 where the passive wireless sensordetermines a change to the operational parameter as result of thesensing (e.g., senses an impedance change by adjusting the tuningcircuit to achieve resonance of the front-end with the carrier frequencyand determine the amount of adjusting to be representative of theimpedance change.)

The method continues at step 154 where the passive wireless sensorgenerates a coded value to represent the change. For example, a five-bitdigital is used to represent the change, where a mid-range valuerepresents little to no change in impedance, a low value represents anotable decrease in impedance, and a high value represent a notableincrease in impedance. Note that dithering may be used to increase theresolution of the coded value (e.g., to eight bits). The passivewireless sensor modulates and up converts (e.g., back-scattering) thecoded value to produce a coded sense response signal, which istransmitted to the sensor computing device in step 156.

The method continues at step 158 where the sensor computing devicereceives the response RF signal that includes the carrier frequencysignal and the coded sense response signal. The method continues at step160 where the sensor computing device generates an environmentalcondition value based on the coded sense response signal and anenvironmental conversion information. For example, the environmentalcondition value is a measure of moisture level as sensed by the passivewireless sensor.

FIG. 7 is a logic diagram of another example of a sensor computingdevice communicating with a passive wireless sensor, which has similarsteps to the method of FIG. 6 (i.e., steps 130-136, 140, and 148-156).The method begins with steps 130-136 and 140, where the passive wirelesssensor sends a RSSI signal to the sensor computing device. The methodcontinues at step 170 where sensor computing device receives an RFresponse signal that includes the RSSI signal. The method continues atstep 172 where the sensor computing device determines a coded valueerror factor based on the received signal strength of the RF signal anda desired received signal strength. As mentioned, the supply voltage andcorresponding current are variables that can also affect the operationalparameter. Thus, to remove the supply voltage and corresponding currentas variables, the computing device determines how different the actualpower level is from the desired power level. Based on this difference,the computing device determines the effect on the operating parameter(e.g., raise it or lower it). The amount of the effect is recorded asthe coded value error factor.

The method continues at step 174 where the computing device receives theRF response signal that includes the carrier frequency and the codedresponse signal. The computing device down converts and/or demodulatesthe RF response signal to recover the coded value of the operationalparameter change at step 176.

The method continues at step 178 where the computing device adjusts thecoded value based on the coded value error factor to produce an adjustedcoded value. The method continues at step 180 where the computing devicegenerates the environmental condition value based on the adjusted codedvalue and the environmental conversion information.

FIG. 8 is a logic diagram of an example of generating an environmentalcondition value based on the environmental conversion information. Themethod begins at step 190 where the computing device determines the typeof environmental condition being sensed by the passive wireless sensor.For example, the passive wireless sensor senses one or more oftemperature, moisture (e.g., absence, presence, amount), pressure,weight, humidity, gas percentages, location proximity, light, and liquidproperties.

The method continues at step 192 where the computing device selects, asthe environmental conversion information, one of a plurality ofenvironmental conversion databases based on the type of environmentalcondition. For instance, each type of sensing will have uniqueenvironmental condition information for converted the coded value intothe environmental condition value. As a specific example, a five-bitcoded value of moisture will have environmental condition information toconvert the five-bit coded value into a specific measure of moisture(e.g., dry, 10% saturated, 50% saturated, 100% saturated).

In an embodiment, each environmental condition information is adatabase, where the coded value is an index to the database fordetermining (e.g., looking up) the actual environmental condition value.In another embodiment, the environmental condition information is one ormore equations for converting the coded value into the actualenvironmental condition value. The environmental condition informationincludes empirical data and/or theoretic data.

The method continues at step 194 where the computing device recovers acoded value from the coded sense response signal. The method continuesat step 196 where the computing device utilizing the coded value as anoperand to the selected environmental conversion database to generatethe environmental condition value. For example, the coded value is anindex operand for looking up a specific value in the selected database.In another example, the coded value is a mathematical operand to one ormore equations of the selected database.

FIG. 9 is a logic diagram of an example of calibrating communicationbetween a sensor computing device communicating and a passive wirelesssensor. The method begins at step 200 where the sensor computing deviceinitiates a calibration process with the passive wireless sensor. Duringcalibration, the passive wireless sensor is subjected to a knownenvironmental condition (e.g., known moisture level, known temperature,known pressure, etc.). For example, the computing devices sends an RFsignal 120 as shown in FIG. 5.

The method continues at step 202 where the sensor computing devicereceives a response calibration RF signal from the passive wirelesssensor. The sensor computing device down converts and/or demodulates theRF signal, which includes the carrier frequency signal and a codedcalibration signal, to produce coded value. The method continues at step204 where the computing device generates a calibration referenceenvironmental condition value based on the coded value and theenvironmental conversion information.

The method continues at step 206 where the computing device compares thecalibration reference environmental condition value with the knownenvironmental condition. If the comparison is favorable (e.g., thecalibrated reference environment condition value indicates a 0%saturation level and the known environmental condition is dry, or 0%saturation), the method continues at step 210 where the computing devicedeems the passive wireless sensor to be calibrated.

If, however, the comparison is not favorable (e.g., the calibratedreference environment condition value indicates a 10% saturation leveland the known environmental condition is dry, or 0% saturation), themethod continues at step 212 or at step 214. At step 212, the computingdevice determines a calibration offset value (e.g., a value added to thecoded value such that resulting saturation level is 0% for thecalibration test) and sends it to the passive wireless device forstorage and subsequent use.

At step 214 the computing device adjusts the environmental conversioninformation based on a difference between the calibration referenceenvironmental condition value and the known environmental condition suchthat the resulting calibration environmental condition valuesubstantially matches the known environmental condition. Note that themeasured environmental condition is affected by the surroundingconditions of the passive wireless sensor. For example, if the passivewireless sensor is mounted on or near a metal surface, the metal surfacewill affect the operational parameter of the passive wireless sensor'sfront end. As another example, if the passive wireless sensor is in anoisy area (e.g., one or more interfering signals), the interferingsignals will affect the operation parameter.

In an alternative method, the computing device initiates a calibrationprocess with the passive wireless sensor that is subjected to a firstknown environmental condition (e.g., dry for a moisture test) and to asecond known condition (e.g., 100% saturated for a moisture test. Forthe first known environmental condition, the passive wireless sensorgenerates a first coded value to represent a change in the operationalparameter of its front end as a result of exposure to the first knownenvironmental condition. The passive wireless sensor sends a firstresponse calibration RF signal that includes the carrier frequencysignal and a first coded calibration signal (i.e., the first codedvalue) to the computing device. The computing device stores the firstcoded value as a first calibrated coded value for the first knowncondition.

For the second known environmental condition, the passive wirelesssensor generates a second coded value to represent a change in theoperational parameter of its front end as a result of exposure to thesecond known environmental condition. The passive wireless sensor sendsa second response calibration RF signal that includes the carrierfrequency signal and a second coded calibration signal (i.e., the secondcoded value) to the computing device. The computing device stores thesecond coded value as a second calibrated coded value for the secondknown condition.

FIG. 10 is a logic diagram of an example of a sensor computing devicecommunicating with multiple passive wireless sensors. The method beginsat step 220 where the sensor computing device is transmitting tomultiple passive wireless sensors (e.g., a first and second sensor). Thecomputing device may utilize time domain multiple access (FDMA),frequency domain multiple access (FDMA), a combination thereof tocommunication with multiple passive wireless sensors, and/or asdescribed in the RFID standard.

To communicate with a first passive wireless sensor, the computingdevice executes steps 222 through 232 and, to communicate with a secondpassive wireless sensor, the computing device executes steps 234-244.Steps 222-232 are similar to steps 234-244. For instance, at steps 222and 234, the computing device receives RSSI signals from the respectivepassive wireless sensors. The method continues to steps 224 and 236where the computing device determines whether the respective RSSIsignals are at the optimal, or desired, level. If not, the methodcontinues at step 226 and/or step 238 where the computing device adjuststhe transmit power and retransmits the RF signal(s).

When the transmit power levels are at the optimum levels, the methodcontinues at steps 228 and 240 where the computing device transits an RFsignal to the respective passive wireless sensor. The RF signal includesa carrier frequency signal (e.g., the same or different for each sensor)and a respective modulated sense request signal. The method continues atsteps 230 and 242 where the computing device receives respectiveresponse RF signal(s) form the sensors. The method continues at steps232 and 244 where the computing device generates respectiveenvironmental condition values based on the respective coded senseresponse signal and the respective environmental conversion information.

FIG. 11 is a diagram of an example of frequency hopping 254 amongchannels 252 within a frequency band 250. For example, the frequencyband 250 includes frequencies in the range of 902 MHz to 928 MHz andincludes 50 channels (e.g., 50 different carrier frequencies). Thefrequency hopping 254 among the channels 252 may be in accordance with astandard (e.g., RFID standard), in accordance with a predeterminedpattern, or in accordance with a random pattern. The time between eachfrequency hop may be standardized, predetermined, or random.

FIG. 12 is a logic diagram of an example of frequency hoppingcommunication between a sensor computing device and a passive wirelesssensor. The method begins at step 260 where the computing devicetransmits, for a first hop of a frequency hopping frequency, the RFsignal to the passive wireless sensor. For the first hop, the RF signalincludes a first carrier frequency signal (e.g., a first channel) and afirst modulated sense request signal. The method continues at step 262where, in response to the first modulated sense request signal, thecomputing device receives a first response RF signal that includes thefirst carrier frequency signal and a first coded sense response signal.

The method continues at step 264 where the computing device recovers afirst coded value from the first coded sense response signal (e.g., afirst representative of the sensed environmental condition by thepassive wireless sensor). The method continues, for a second frequencyhop (e.g., a second carrier frequency or channel), at steps 266-270,where the computing devices recovers a second coded value. The methodcontinues through “n” frequency hops where, at steps 272-276, thecomputing device recovers an “nth” coded value. Note that variances inthe carrier frequency (e.g., using different channels) cause variancesin the operational condition of the passive wireless sensor's front end.Further note that to execute the frequency hopping, the transceiver 70includes a software defined radio that the computing device configuresto accommodate the desired commutation with the passive wireless sensor.

The method continues at step 278 where the computing device generatesthe environmental condition value based on the “n” coded sense responsesignals (or a subset thereof), the environmental conversion information,and the carrier frequency signals. For example, the computing deviceaverages the coded values to produce the final environmental conditionvalue.

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, audio, etc. any of which may generally be referred to as‘data’).

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “configured to”, “operably coupled to”, “coupled to”, and/or“coupling” includes direct coupling between items and/or indirectcoupling between items via an intervening item (e.g., an item includes,but is not limited to, a component, an element, a circuit, and/or amodule) where, for an example of indirect coupling, the intervening itemdoes not modify the information of a signal but may adjust its currentlevel, voltage level, and/or power level. As may further be used herein,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two items inthe same manner as “coupled to”. As may even further be used herein, theterm “configured to”, “operable to”, “coupled to”, or “operably coupledto” indicates that an item includes one or more of power connections,input(s), output(s), etc., to perform, when activated, one or more itscorresponding functions and may further include inferred coupling to oneor more other items. As may still further be used herein, the term“associated with”, includes direct and/or indirect coupling of separateitems and/or one item being embedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, and/or “processing unit” may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may be, or furtherinclude, memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of another processing module, module, processing circuit,and/or processing unit. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from figureto figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method comprises: transmitting, by a computingdevice, a radio frequency (RF) signal to a passive wireless sensor,wherein the RF signal includes a carrier frequency signal and amodulated sense request signal, and wherein the RF signal is downconverted and demodulated by the passive wireless sensor to recover asense request signal of the modulated sense response signal; in responseto the modulated sense request signal, receiving, by the computingdevice, a response RF signal that includes the carrier frequency signaland a coded sense response signal from the passive wireless sensor,wherein the coded sense response signal is representative of a sensedenvironmental condition by the passive wireless sensor, wherein thesensed environmental condition affects impedance of a front-end of thepassive wireless sensor to produce an affected impedance; and whereinthe passive wireless sensor generates the coded sense response signalbased on tuning the affected impedance to resonate with the carrierfrequency signal; and generating, by the computing device, anenvironmental condition value based on the coded sense response signaland an environmental conversion information.
 2. The method of claim 1further comprises: prior to receiving the response RF signal, receiving,by the computing device, another response RF signal that includes thecarrier frequency and a received power level indication signal that isrepresentative of received signal strength of the RF signal;determining, by the computing device, whether the received signalstrength of the RF signal is at a desired level for enabling thewireless sensor to generate an accurate coded sense response signal;when the received signal strength of the RF signal is not at the desiredlevel: adjusting, by the computing device, transmit power of the RFsignal; and transmitting, by the computing device, the RF signal at anadjusted transmit power level.
 3. The method of claim 1 furthercomprises: receiving, by the computing device, another response RFsignal that includes the carrier frequency and a received power levelindication signal that is representative of received signal strength ofthe RF signal; determining, by the computing device, a coded value errorfactor based on the received signal strength of the RF signal and adesired received signal strength; adjusting, by the computing device, acoded value of the coded sensed response signal based on the coded valueerror factor to produce an adjusted coded value; and generating, by thecomputing device, the environmental condition value based on theadjusted coded value and the environmental conversion information. 4.The method of claim 1 further comprises: generating, by the passivewireless sensor, a power supply voltage from the carrier frequencysignal; down converting, by the passive wireless sensor, the RF signalto recover the sense request signal; tuning, by the passive wirelesssensor, the impedance of the front-end of the passive wireless sensor toresonate with the carrier frequency, wherein the front-end includes asensing element for sensing an environmental condition and wherein thesensing of the environmental condition by the sensing element alters theimpedance of the front-end; and generating, by the passive wirelesssensor, the coded sense response signal as a representation of thetuning of the impedance of the front-end.
 5. The method of claim 4,wherein the generating the environmental condition value comprises:determining a type of environmental condition being sensed by thepassive wireless sensor; selecting, as the environmental conversioninformation, one of a plurality of environmental conversion databasesbased on the type of environmental condition; recovering a coded valuefrom the coded sense response signal; and utilizing the coded value asan operand to the one of the plurality of environmental conversiondatabases to generate the environmental condition value.
 6. The methodof claim 1 further comprises: configuring, by the computing device, asoftware define transceiver for communicating with the passive wirelesssensor.
 7. The method of claim 1 further comprises: initiating, by thecomputing device, a calibration process with the passive wirelesssensor, wherein the passive wireless sensor is subjected to a knownenvironmental condition; receiving, by the computing device, a responsecalibration RF signal that includes the carrier frequency signal and acoded calibration signal from the passive wireless sensor, wherein thecoded calibration signal is representative of the known environmentalcondition by the passive wireless sensor; generating, by the computingdevice, a calibration reference environmental condition value based onthe coded calibration signal and the environmental conversioninformation; comparing, by the computing device, the calibrationreference environmental condition value with the known environmentalcondition; when the calibration reference environmental condition valuecompares unfavorably with the known environmental condition: adjusting,by the computing device, the environmental conversion information basedon a difference between the calibration reference environmentalcondition value and the known environmental condition; or sending, bythe computing device, a calibration offset to the passive wirelesssensor, wherein the passive wireless sensor utilizes the calibrationoffset when generating the coded sense response signal such that thecoded sense response signal is a more accurate representation of thesensed environmental condition.
 8. The method of claim 1 furthercomprises: transmitting, by the computing device, a second RF signal toa second passive wireless sensor, wherein the second RF signal includesthe carrier frequency signal and a second modulated sense requestsignal, and wherein the second RF signal is down converted anddemodulated by the second passive wireless sensor to recover a secondsense request signal of the second modulated sense response signal; inresponse to the second modulated sense request signal, receiving, by thecomputing device, a second response RF signal that includes the carrierfrequency signal and a second coded sense response signal from thesecond passive wireless sensor, wherein the coded sense response signalis representative of a second sensed environmental condition by thesecond passive wireless sensor, wherein the second sensed environmentalcondition affects the impedance of a second front-end of the secondpassive wireless sensor to produce a second affected impedance; andwherein the second passive wireless sensor generates the second codedsense response signal based on by tuning the second affected impedanceto resonate with the carrier frequency signal; and generating, by thecomputing device, a second environmental condition value based on thesecond coded sense response signal and second environmental conversioninformation.
 9. The method of claim 1 further comprises: transmitting,by the computing device, the RF signal to the passive wireless sensorusing a frequency hopping scheme, wherein the RF signal includes, for afirst hop of the frequency hopping scheme, a first carrier frequencysignal of a plurality of carrier frequency signals and the modulatedsense request signal and includes, for a second hop of the frequencyhopping scheme, a second carrier frequency signal of the plurality ofcarrier frequency signals and the modulated sense request signal; inresponse to the modulated sense request signal: receiving, by thecomputing device, a first response RF signal that includes the firstcarrier frequency signal and a first coded sense response signal fromthe passive wireless sensor, wherein the first coded sense responsesignal is a first representative of the sensed environmental conditionby the passive wireless sensor; receiving, by the computing device, asecond response RF signal that includes the second carrier frequencysignal and a second coded sense response signal from the passivewireless sensor, wherein the second coded sense response signal is asecond representative of the sensed environmental condition by thepassive wireless sensor; and generating, by the computing device, theenvironmental condition value based on the first and second coded senseresponse signal, the environmental conversion information, the firstcarrier frequency signal, and the second carrier frequency signal. 10.The method of claim 1, wherein the environmental condition value is ameasure of one of: temperature; moisture; pressure; weight; humidity;gas percentages; location proximity; light; and liquid properties. 11.The method of claim 1 further comprises: initiating, by the computingdevice, a calibration process with the passive wireless sensor, whereinthe passive wireless sensor is subjected to a first known environmentalcondition and to a second known condition; receiving, by the computingdevice, a first response calibration RF signal that includes the carrierfrequency signal and a first coded calibration signal from the passivewireless sensor, wherein the first coded calibration signal includes afirst coded value corresponding to a measurement of the first knownenvironmental condition by the passive wireless sensor; receiving, bythe computing device, a second response calibration RF signal thatincludes the carrier frequency signal and a second coded calibrationsignal from the passive wireless sensor, wherein the second codedcalibration signal includes a second coded value corresponding to ameasurement of the second known environmental condition by the passivewireless sensor; storing, by the computing device, the first coded valueas a first calibrated coded value for the first known condition; andstoring, by the computing device, the second coded value as a secondcalibrated coded value for the second known condition.
 12. A computingdevice comprises: a transceiver; memory; a processing module operablycoupled to the transceiver and the memory, wherein the processing moduleis operable to: transmit, via the transceiver, a radio frequency (RF)signal to a passive wireless sensor, wherein the RF signal includes acarrier frequency signal and a modulated sense request signal, andwherein the RF signal is down converted and demodulated by the passivewireless sensor to recover a sense request signal of the modulated senseresponse signal; in response to the modulated sense request signal,receive, via the transceiver, a response RF signal that includes thecarrier frequency signal and a coded sense response signal from thepassive wireless sensor, wherein the coded sense response signal isrepresentative of a sensed environmental condition by the passivewireless sensor, wherein the sensed environmental condition affectsimpedance of a front-end of the passive wireless sensor to produce anaffected impedance; and wherein the passive wireless sensor generatesthe coded sense response signal based on tuning the affected impedanceto resonate with the carrier frequency signal; and generate anenvironmental condition value based on the coded sense response signaland an environmental conversion information.
 13. The computing device ofclaim 12, wherein the processing module is further operable to: prior toreceiving the response RF signal, receive, via the transceiver, anotherresponse RF signal that includes the carrier frequency and a receivedpower level indication signal that is representative of received signalstrength of the RF signal; determine whether the received signalstrength of the RF signal is at a desired level for enabling thewireless sensor to generate an accurate coded sense response signal;when the received signal strength of the RF signal is not at the desiredlevel: adjust transmit power of the RF signal; and transmit, via thetransceiver, the RF signal at an adjusted transmit power level.
 14. Thecomputing device of claim 12, wherein the processing module is furtheroperable to: receive, via the transceiver, another response RF signalthat includes the carrier frequency and a received power levelindication signal that is representative of received signal strength ofthe RF signal; determine a coded value error factor based on thereceived signal strength of the RF signal and a desired received signalstrength; adjust a coded value of the coded sensed response signal basedon the coded value error factor to produce an adjusted coded value; andgenerate the environmental condition value based on the adjusted codedvalue and the environmental conversion information.
 15. The computingdevice of claim 12, wherein the processing module is further operable togenerate the environmental condition value by: determining a type ofenvironmental condition being sensed by the passive wireless sensor;selecting, as the environmental conversion information, one of aplurality of environmental conversion databases based on the type ofenvironmental condition; recovering a coded value from the coded senseresponse signal; and utilizing the coded value as an operand to the oneof the plurality of environmental conversion databases to generate theenvironmental condition value.
 16. The computing device of claim 12further comprises: the transceiver including a software definetransceiver; and the processing module is further operable to furtheroperable to configure the software define transceiver for communicatingwith the passive wireless sensor.
 17. The computing device of claim 12,wherein the processing module is further operable to: initiate acalibration process with the passive wireless sensor, wherein thepassive wireless sensor is subjected to a known environmental condition;receive, via the transceiver, a response calibration RF signal thatincludes the carrier frequency signal and a coded calibration signalfrom the passive wireless sensor, wherein the coded calibration signalis representative of the known environmental condition by the passivewireless sensor; generate a calibration reference environmentalcondition value based on the coded calibration signal and theenvironmental conversion information; compare the calibration referenceenvironmental condition value with the known environmental condition;when the calibration reference environmental condition value comparesunfavorably with the known environmental condition: adjust theenvironmental conversion information based on a difference between thecalibration reference environmental condition value and the knownenvironmental condition; or send, via the transceiver, a calibrationoffset to the passive wireless sensor, wherein the passive wirelesssensor utilizes the calibration offset when generating the coded senseresponse signal such that the coded sense response signal is a moreaccurate representation of the sensed environmental condition.
 18. Thecomputing device of claim 12, wherein the processing module is furtheroperable to: transmit, via the transceiver, a second RF signal to asecond passive wireless sensor, wherein the second RF signal includesthe carrier frequency signal and a second modulated sense requestsignal, and wherein the second RF signal is down converted anddemodulated by the second passive wireless sensor to recover a secondsense request signal of the second modulated sense response signal; inresponse to the second modulated sense request signal, receive, via thetransceiver, a second response RF signal that includes the carrierfrequency signal and a second coded sense response signal from thesecond passive wireless sensor, wherein the coded sense response signalis representative of a second sensed environmental condition by thesecond passive wireless sensor, wherein the second sensed environmentalcondition affects the impedance of a second front-end of the secondpassive wireless sensor to produce a second affected impedance; andwherein the second passive wireless sensor generates the second codedsense response signal based on by tuning the second affected impedanceto resonate with the carrier frequency signal; and generate a secondenvironmental condition value based on the second coded sense responsesignal and second environmental conversion information.
 19. Thecomputing device of claim 12, wherein the processing module is furtheroperable to: transmit, via the transmitter, the RF signal to the passivewireless sensor using a frequency hopping scheme, wherein the RF signalincludes, for a first hop of the frequency hopping scheme, a firstcarrier frequency signal of a plurality of carrier frequency signals andthe modulated sense request signal and includes, for a second hop of thefrequency hopping scheme, a second carrier frequency signal of theplurality of carrier frequency signals and the modulated sense requestsignal; in response to the modulated sense request signal: receive, viathe transceiver, a first response RF signal that includes the firstcarrier frequency signal and a first coded sense response signal fromthe passive wireless sensor, wherein the first coded sense responsesignal is a first representative of the sensed environmental conditionby the passive wireless sensor; receive, via the transceiver, a secondresponse RF signal that includes the second carrier frequency signal anda second coded sense response signal from the passive wireless sensor,wherein the second coded sense response signal is a secondrepresentative of the sensed environmental condition by the passivewireless sensor; and generate the environmental condition value based onthe first and second coded sense response signal, the environmentalconversion information, the first carrier frequency signal, and thesecond carrier frequency signal.
 20. The computing device of claim 12,wherein the environmental condition value is a measure of one of:temperature; moisture; pressure; humidity; gas percentages; locationproximity; light; and liquid properties.
 21. The computing device ofclaim 12, wherein the processing module is further operable to: initiatea calibration process with the passive wireless sensor, wherein thepassive wireless sensor is subjected to a first known environmentalcondition and to a second known condition; receive, via the transceiver,a first response calibration RF signal that includes the carrierfrequency signal and a first coded calibration signal from the passivewireless sensor, wherein the first coded calibration signal includes afirst coded value corresponding to a measurement of the first knownenvironmental condition by the passive wireless sensor; receive, via thetransceiver, a second response calibration RF signal that includes thecarrier frequency signal and a second coded calibration signal from thepassive wireless sensor, wherein the second coded calibration signalincludes a second coded value corresponding to a measurement of thesecond known environmental condition by the passive wireless sensor;store the first coded value as a first calibrated coded value for thefirst known condition; and store the second coded value as a secondcalibrated coded value for the second known condition.